Wear Behaviour of Ductile Irons in Continuous Sliding Motion
Prihti, Tomi (2011)
2011
Materiaalitekniikan koulutusohjelma
Automaatio-, kone- ja materiaalitekniikan tiedekunta - Faculty of Automation, Mechanical and Materials Engineering
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Hyväksymispäivämäärä
2011-05-04
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-2011051814673
https://urn.fi/URN:NBN:fi:tty-2011051814673
Tiivistelmä
This Master of Science thesis is carried out for Componenta Ltd. Componenta is one of the largest cast component suppliers in Europe. The thesis is also part of the DEMAPP research program launched by FIMECC Ltd. DEMAPP program develops novel breakthrough materials with improved performance for applications in demanding operational and service environments.
Ductile irons are considered to be ideal materials for a wide range of wear applications, especially frictional wear under both dry and lubricated conditions. However, the discussion of wear resistance of ductile irons is mostly limited to general level due to the large variety of test methods, with each test concentrating to a specific set of conditions. The aim of this Master of Science thesis is to study the wear of different ductile iron grades in continuous sliding motion against steel. The main goal is to get comparable information on wear resistance and wear behaviour of selected ductile irons under specific conditions.
The theoretical part is discussing the properties of the studied materials and wear phenomena. The general wear mechanisms and variables influencing wear are presented along with the existing knowledge on the wear of ductile irons on the basis of literature review.
The experimental work consists of sample preparation and sample holder design, preliminary and actual wear tests and of the analysis of worn samples. The wear tests are run in VTT Otaniemi with a pin-on-disc tribotester using special sample geometry. The studied ductile irons are used as disc material and steel wire as pin material. The total number of 10 different EN-standard ductile iron grades are used in the wear tests, including austempered and solution strengthened grades. The tests are carried out under dry and lubricated conditions using constant test parameters.
According to the wear test results, austempered grades seem to wear much slower than the others. In fact, the wear rate was found to be negative, indicating that there is more material transferred into the surface of ADI discs than has been worn off. This is understandable, as the pin wear was increased along with the hardness of the disc. The novel high silicon ductile iron grades also showed promising wear results both under dry and lubricated sliding conditions. There was also an intention to study the actual wear mechanisms with SEM, but due to a lack of time this will be carried out as an additional study. /KIr11
Ductile irons are considered to be ideal materials for a wide range of wear applications, especially frictional wear under both dry and lubricated conditions. However, the discussion of wear resistance of ductile irons is mostly limited to general level due to the large variety of test methods, with each test concentrating to a specific set of conditions. The aim of this Master of Science thesis is to study the wear of different ductile iron grades in continuous sliding motion against steel. The main goal is to get comparable information on wear resistance and wear behaviour of selected ductile irons under specific conditions.
The theoretical part is discussing the properties of the studied materials and wear phenomena. The general wear mechanisms and variables influencing wear are presented along with the existing knowledge on the wear of ductile irons on the basis of literature review.
The experimental work consists of sample preparation and sample holder design, preliminary and actual wear tests and of the analysis of worn samples. The wear tests are run in VTT Otaniemi with a pin-on-disc tribotester using special sample geometry. The studied ductile irons are used as disc material and steel wire as pin material. The total number of 10 different EN-standard ductile iron grades are used in the wear tests, including austempered and solution strengthened grades. The tests are carried out under dry and lubricated conditions using constant test parameters.
According to the wear test results, austempered grades seem to wear much slower than the others. In fact, the wear rate was found to be negative, indicating that there is more material transferred into the surface of ADI discs than has been worn off. This is understandable, as the pin wear was increased along with the hardness of the disc. The novel high silicon ductile iron grades also showed promising wear results both under dry and lubricated sliding conditions. There was also an intention to study the actual wear mechanisms with SEM, but due to a lack of time this will be carried out as an additional study. /KIr11